> I would look for a shorted tantalum capacitor hanging
> somewhere on the
> 10V rail.
I agree.
> If you hook 10V from an outside source to the 10V
> buss, you'll
> probably find it's drawing all kinds of current. The 10V regulator
> circuit will go into fold back before burning up. This is by
> design. I
> usually hook a source of 10V at about 1.5A and look for smoke. It's
> usually one of the tantalum capacitors that starts to smoke.
> Once it's
> done smoking, problem solved!!
Put a DMM on the 10V line, then start disconnecting things until you narrow
it down, divide and conquer. Pull all of the cards out of the cage (except
the 10V reg card obviously), disconnect the exciter, remove the receiver,
etc. With a good ohmmeter that measures fractions of an ohm, you should be
able to narrow it down further once you've found the suspect module/board.
> I have lost track of how many shorted tantalums I have had over the
> years. When they occur in the B+ of the high current PA supply, they
> simply burn up and th problem fixes itself.
They make a cool purple smoke with lots of sparks when they flame out!
--- Jeff WN3A
